1. Field of the Invention
The present invention relates to an ink jet printer that prints a desired image (this including writing) on a printing sheet by discharging ink towards the printing sheet. In particular, the present invention relates to an ink jet printer in which a mechanism has been improved that rotates an endless belt used for feeding the printing sheet.
2. Description of the Related Art
An ink jet printer discharges ink from nozzles formed in a printing head. The ink that has been discharged is deposited on a printing sheet at a printing position, thus printing a desired image on the printing sheet. In order to feed the printing sheet to the printing position, the ink jet printer is provided with a pair of rollers and an endless belt wound across the pair of rollers. A support plate is frequently used that supports the endless belt at a location between the pair of rollers. The support plate supports an inner face of the endless belt from bellow. The support plate prevents the endless belt from bending downwards.
In this ink jet printer, when no ink is discharged from the nozzles for a long period, a surface of the ink within the nozzles may dry out, causing deterioration in ink discharge. In order to prevent this occurring, a flushing action is periodically executed, i.e. ink is forcibly discharged from the nozzles towards a location other than the printing sheet.
Ink jet printers come in both the serial type and the line type. With serial type ink jet printers, the printing head moves back and forth in a direction orthogonal to a feeding direction of the printing sheet. With serial type ink jet printers, the printing head is moved to a position outside the width of the printing sheet when the flushing action is to be executed, and ink is forcibly discharged from the nozzles towards this position outside the width of the printing sheet.
With line type ink jet printers, the printing head is fixed to a main body of the ink jet printer, and extends along the direction orthogonal to the feeding direction of the printing sheet. When the flushing action is executed with line type ink jet printers, ink may be forcibly discharged from the nozzles into a cavity formed in an outer face of the endless belt. This technique is taught in Japanese Laid-Open Patent Application Publication No. 2004-136664.
In both serial type and line type ink jet printers, maintenance must be performed on the printing head. During maintenance, a flexible blade made from rubber or the like wipes an anterior face (the face in which the nozzles are formed) of the printing head so as to remove foreign matter from the nozzles. At this juncture, ink may be splashed onto the endless belt.
Furthermore, if the printing sheet becomes jammed within the ink jet printer, ink may be discharged onto the endless belt. This may occur in both the serial and line type ink jet printers.